“Apparently she thought Labor Day weekend meant LABOR day weekend… Look who showed up three weeks early! On Sept. 4th we welcomed little Miss Sierra Esther Ruah Olsen,” the actress captioned a family photo.

“She entered the world in her own way — breeched! I was a good candidate to deliver her naturally so I needed to find a doctor in L.A. who would know how to do it. Fortunately I found one of the few… Healthy & happy mommy & baby walked out of the hospital 24hrs later. I had an OB and doula assisted birth at Cedars-Sinai, and the #love and #support of my wonderful #hubby This photo is the perfect representation of everything I’ve ever wanted.”

Ruah — who broke her pregnancy news on the social media app in April — and Olsen also share son River Isaac, 2½.

via @danielaruah insagram

The happy parents met on the set of NCIS: Los Angeles, on which the 32-year-old plays Special Agent Kensi Blye. Olsen, a former Navy SEAL, has acted as his younger brother Eric Christian Olsen‘s stunt double in the past. Eric’s own wife, Sarah Wright Olsen, also gave birth to a baby girl this summer. The couple welcomed Esmé Olivia on Aug. 9.

Ruah’s pregnancy comes after heartbreak: she experienced a miscarriage last October at nine weeks along.

“Something like that hits you physically, emotionally and psychologically, but my doctor said, ‘Even if you sat on my table the whole time, this still would’ve happened. You have to try again,’ ” Ruah told Fit Pregnancy and Baby for the magazine’s September cover story.

That “second try,” was when the pair conceived their little girl.

She said, “Nature is a beautiful thing — it does what it needs to do when it needs to do it.”